Scientists have identified a protein that could be an early indicator for Alzheimer's disease, it emerged today.

Researchers found that higher concentrations of clusterin, a protein in the blood plasma, appear to be associated with the development, severity and progression of the condition.

It is hoped the breakthrough could lead to the development of a simple blood test for detecting Alzheimer's, one of the most common forms of dementia in the UK.

The King's College, London-based team studied clusterin levels in 689 people - including 464 with the illness - - and found a link between higher levels of the protein and severity of disease in the brain area known as the entorhinal cortex, which plays a role in memory.

Increased clusterin in the blood was also associated with having more of the amyloid-beta protein - which form some of the brain abnormalities behind Alzheimer's.

The report authors said: "Although these findings do not support the clinical utility of plasma clusterin concentration as a stand-alone biomarker for Alzheimer's disease, they reveal a robust peripheral signature of this....protein that is responsive to key features of disease pathology."

They added: "Our findings clearly implicate clusterin, but there may well be other proteins in plasma related to the disease process, and indeed our previous studies and those of others suggest this is the case.

"These results may have wider implications for the identification of other...proteins in plasma, both as putative Alzheimer's disease biomarkers as well as drug targets of disease-modifying treatments."